planted in a mix of sand and soil , in a functional refrigerator since Nov 1
Now you must remove them from the refrigerator and let them germinate!
They should be hardy in your area, so I'm not sure why the top growth died. However, English walnut trees are usually grafted, so the suckers coming back from the roots are from the rootstalk, so you don't want to propagate the tree from those.
You can remove it by cutting down the dead growth and applying a stump killer.
Thank you for letting us know that the Walnut trees should be fertilized in the spring, not during the summer. One of the trees is planted in the lawn. When should the fertilizer for the tree be applied; before or after Weed and Feed for the lawn is applied?
You need a grass-free area around your tree that extends to the canopy. Cover it with a couple inches of mulch. Your tree should not be getting your lawn fertilizers and weed killers. Especially avoid getting weed and feed on it. It has weed killers that could harm the tree.
Thr tree is very old and large/tall but very healthy. I need to reduce the size. It is now September and the tree is full of fruit so I am reluctant to cut at this time. Am I able to cut in mid to late October? I am situated in south west France so that time of year is relatively warm.
Generally, you want to cut closer to the end of dormancy, but while the tree is still dormant. This article will help:
Hi, I have a well laden branch break off my English walnut tree, can I save the walnuts or do I need to dispose of them all?
I understand they will ripen off the tree, but it may take about 5 weeks.